PITTSBURGH – The Astros’ makeshift outfield fell apart in the bottom of the ninth inning with two outs and the bases loaded.

Facing a 3-2 count, the Pirates’ Russell Martin blooped a high pop fly into shallow right field. Second baseman Jake Elmore ran backward, right fielder Jimmy Paredes ran in, the two collided, the ball hit the field and Martin received a walk-off via an E-9 during Pittsburgh’s 5-4 interleague victory Friday at PNC Park.

Pittsburgh’s (25-17) Andrew McCutchen singled to right off reliever Edgar Gonzalez with a runner on first and one out in the ninth to put the Pirates in scoring position. Brandon Inge’s light comebacker to the mound resulted in a no-throw and an error on Gonzalez, loading the bases. After Neil Walker struck out looking, Russell Martin took the count to 3-2 with two outs.

The Astros (11-31) carried a 4-2 lead into the bottom of the eighth. But reliever Hector Ambriz gave up a one-out, two-run homer to Pittsburgh’s Pedro Alvarez that flew 462 feet, shooting out of PNC and into the Allegheny River.

Astros starting righthander Jordan Lyles allowed four hits and two runs (one earned) while striking out four in five-plus innings.

Pirates Jeanmar Gomez gave up five hits and four runs (three earned) in 4 2/3 innings.

The Astros jumped ahead 1-0 in the first with National League-style ball. Former Pirate prospect Robbie Grossman led off with a sharp double to center field. He took third after Jake Elmore’s sacrifice bunt, then scored on Jason Castro’s sac fly.

Pittsburgh evened the contest in the bottom of the frame when McCutchen homered to deep left-center field. Lyles threw 32 pitches in the inning but limited the damage to a single run by getting Russell Martin to ground out with two runners on base.

Four scoreless innings followed before Astros third baseman Matt Dominguez hit his third home run of the season into the left-field stands in the top of the fifth, giving the Astros a 2-1 lead. Jake Elmore’s RBI single and two Pirates errors increased the Astros’ advantage to 4-1.

Right fielder Chris Carter – normally a left fielder – dropped a soft McCutchen fly ball in the sixth and Pittsburgh pulled within two runs via Garrett Jones’ RBI double to center. Reliever Paul Clemens ended the inning with a Jody Mercer pop up to Elmore, ending a two-out bases-loaded threat.